The core tools are mostly LAMP-based (Linux, Apache, MySQL, PHP). However, there are discrete components within Blunder which can be used outside of this framework.
Most of Blunder is released under the GNU GPL Version 3 license. A few parts are under other free licenses. See licensing for more details.
Currently Blunder can be grabbed from git source control. The core web-php component has been in beta for some time, and has worked well. The Java jar file that converts chess PGN to FEN format is under active development, and just entered beta. We will release a tarball when the beta testing of the PGN to FEN converter enters completion. While we are putting finishing touches on the PGN to FEN converter, and beta testing the whole suite, Blunder is in quite usable condition right now - we have been using it for over a year to happy result.
Project details - Git source repository, discussion forums etc.